Latex made up of all acrylic polymers are known for their toughness, good water resistance, and excellent scrub and stain resistance when used as binders in paints. On the other hand, vinyl acrylic latex polymers (e.g. a copolymer of vinyl acetate and acrylic monomer) have the unique property of longer open time and ease of application due to its hydrophilic nature, which allows water to remain in the film longer. However, polymer resins made with vinyl acetate are more prone to water sensitivity. Vinyl acetate monomers are also more economical than their acrylic counterparts. Alone, acrylic and vinyl acetate latexes have desirable properties; however, blending of an all-acrylic polymer and a vinyl acrylic polymer may compromise the overall performance of the latex, and compatibility issues of the two different polymers may arise.
Core-shell copolymer has found relevance in a variety of applications including adhesives, binder, inks, paints and architectural coatings. Generally, core-shell copolymers are prepared by a stepwise emulsion polymerization, a first step produces a core polymer or a first phase and a second step produces a shell polymer or a second phase. The shell polymer contributes to the film property and the core polymer imparts the mechanical strength to the latex.
However, there remains a need for an improved polymer that has the properties of good durability, long open time, good flow and leveling, easy application, and good water sensitivity, and can be made with cost effective starting materials.